海角大神

Jessica Mendoza: Welcome to 鈥淩ethinking the News鈥� by 海角大神. I鈥檓 Jessica Mendoza, one of the producers. Today, we鈥檙e releasing the second episode in our new six-part science series, 鈥淚t鈥檚 About Time,鈥� hosted by Rebecca Asoulin and Eoin O鈥機arroll. If you haven鈥檛 listened to our 1st episode, check it out! OK, let鈥檚 get started.聽

[Music]

Rebecca: This is 鈥淚t鈥檚 About Time.鈥� A series all about...

Eoin O鈥機arroll: Time. I鈥檓 Eoin O鈥機arroll.聽

Rebecca: And I鈥檓 Rebecca Asoulin.聽

Eoin: In this science series, we interview experts on time. They鈥檒l help us unravel its mysteries.

Rebecca: Because understanding time more deeply can help us make the most of the time we have.聽

[Music]

Rebecca: So what is time?聽

Eoin: According to Oxford University Press, 鈥渢ime鈥� is the in the English language. We use it all the time. Yet we find it so hard to define.

Rebecca: We spoke to a lot of time experts for this series. And we asked every one of them to define time for us. They all struggled. And when they did finally define it, their definitions were really different.聽

Eoin: That鈥檚 Heather Dyke, a philosopher of time. What she鈥檚 saying is: Time is hard to define because it鈥檚 just sort of there. It鈥檚 such a slippery concept.聽

Rebecca: This episode is about diving deep into that concept. We鈥檒l talk to a philosopher, a physicist, and a novelist who have all made it their life鈥檚 work to answer the question: what is time? And maybe by trying to figure out what time is and how it works, we can learn a little about how to reframe the challenges in our own lives.聽

[Music]

Rebecca: So I鈥檝e personally always found philosophy kind of baffling. It just never seemed that useful to me in terms of people鈥檚 day-to-day lives.

Eoin: I mean, philosophy is aimed at the most baffling questions. The ones that can鈥檛 be settled by normal science. So if you鈥檙e not baffled on some level, I think you鈥檙e not doing it right.聽聽

Rebecca: Comforting, very comforting, Eoin.

Eoin:聽 But, you know, I think philosophy鈥檚 also unavoidable.聽

搁别产别肠肠补:听This is Heather Dyke again. She鈥檚 a philosopher of time at the University of Otago, in Dunedin New Zealand. Heather says her goal as a philosopher is to understand time in itself. And how time connects to all different parts of our lives 鈥� from the politics of time, to the psychology of time.

Eoin: Heather鈥檚 understanding of time as a philosopher helped her put into perspective a difficult personal decision.

Rebecca: That decision centered around an 18th century manor house in the English countryside.聽

Rebecca: Just what you鈥檇 expect if you watch any BBC drama.

Rebecca: Heather moved to the house when she was 12. And she used to visit it before then.

Rebecca: By 2012, Heather has moved to New Zealand, and lives with her husband and children. And she realizes that she needs to make a decision, because 300 years really does a number on a place. Should they try to save the house or sell it?聽

Rebecca: Heather decides she wants to try to turn it around which would mean making enough money to keep up the maintenance of the house. So she moves with her family from New Zealand back to England. And they try to make it work.聽But after seven years of trying, it becomes obvious that the house can鈥檛 be saved.

[Music]

Rebecca: You might be thinking: what does any of this have to do with time? The decision felt like the right thing to do. But it was still really painful. And her philosophy on time actually helped her come to terms with what happened.聽

Heather subscribes to a philosophical theory of time called the B theory.聽

Rebecca:聽What she鈥檚 saying is all times exist, regardless of whether we鈥檙e perceiving it or not. So Eoin chatting with me right now in 2021 is as real as Eoin back in let鈥檚 say, 1990.

Rebecca: In the B theory, there is no present moment. We label things 鈥減ast,鈥� 鈥減resent,鈥� and 鈥渇uture鈥� to match up with our perception of the world. But what we consider the present isn鈥檛 special in this theory. I know this is mind blowing. It鈥檚 really counterintuitive to our experience.聽

But Heather says it鈥檚 how time really works. And the theory is really comforting to her. So back to the manor house.聽

Rebecca: For Heather, when something bad happens, it鈥檚 comforting for her to know that our decisions, aren鈥檛 the only reason things turned out the way they did. To her, the future is not totally limitless. Whether or not the theory is true, it resonates with Heather and helped her deal with the pain of selling her family鈥檚 house.

[Music]

Rebecca: The B theory鈥檚 foundation is built off of physics. In particular, Albert Einstein鈥檚 theory of special relativity.聽Physics is foundational to many understandings of time.

Eoin: Time 鈥� if it really exists 鈥� is a characteristic of the physical universe. So if we鈥檙e going to find out what time really is, it makes sense to ask a physicist.

[Music]

Eoin: That鈥檚 physicist Ron Mallett. He became a physicist because he wanted to build a time machine. Yes you heard that right.聽 And he succeeded, kind of. He says he actually came up with a design for a real time machine. Well, a real hypothetical time machine, with real science. And lasers!

Rebecca: A childhood tragedy led to Dr. Mallett鈥檚 desire to do that.聽聽

Eoin: Growing up, Dr. Mallett鈥檚 dad would give him scientific toys, and he inspired his love of reading. Then when Dr. Mallett was 10, his father 鈥�

Eoin: His father鈥檚 death plunged the family into poverty. His mom was now a single Black mother, in 1955, with four children to raise.聽

Eoin: 鈥溾�� was written in 1895. It tells a story of a man who travels hundreds of thousands of years into the future.聽

Eoin:聽This quote is from the Time Traveler, the book鈥檚 main character. It鈥檚 part of his explanation of how his time machine works, which treats time as though it were a fourth spatial dimension.聽

Eoin: After all, Dr. Mallett was 10 years old at the time. But that first failure didn鈥檛 stop him. A few years later, he found another book at the Salvation Army.

Eoin: That book was called 鈥�.鈥澛�

[Music]

Eoin: And so Dr. Mallett becomes a theoretical physicist specializing in Albert Einstein鈥檚 general theory of relativity, using it to create a theoretical time machine. He says he showed that it鈥檚 mathematically possible to use lasers to bend time back on itself.聽

To understand how Dr. Mallett does that, we first need to talk about Einstein and his theory of relativity 鈥� there are actually sort of two theories, really. Einstein鈥檚 work is the basis of Dr. Mallett鈥檚 real hypothetical time machine.聽

Rebecca: It鈥檚 also the foundation of physicists鈥� modern understanding of how time works.聽

贰辞颈苍:听First, we鈥檒l talk about Einstein鈥檚 special theory of relativity.聽

[Music]

Eoin: Let鈥檚 say the vehicle is going at 60 miles an hour, and the ball that your friend is throwing is going at 10 miles an hour.聽

Eoin: If you鈥檙e in the car, the ball is going 10 miles an hour. But if you鈥檙e standing outside the car, you鈥檒l see that ball coming at you at 70 miles an hour. In other words, how fast something moves depends on your frame of reference.聽

But, by the beginning of the 20th century, physicists had hit a stumbling block. This principle did not apply to light. Light seemed to travel at the same speed, regardless of how fast the observer was moving.

Rebecca: And that鈥檚 weird. Because everything else changes depending on your frame of reference. And so 鈥�

Rebecca: And that is the Special Theory of Relativity.聽

Eoin: This was totally revolutionary. It created a whole new world for physicists to explore. Before this, everyone thought time was absolute. Now they understood it was actually relative. (Hence, relativity!) Special relativity became the basis for Einstein鈥檚 theory of gravitation, which he called general relativity.聽

搁别产别肠肠补:听The general theory was what Dr. Mallett based his time machine math on.

This stuff is complicated. Dr. Mallett has spent his entire career on this topic. Einstein developing the theory. It just takes some time to absorb.聽

Eoin: Einstein鈥檚 basic idea was that gravity bends space and time.

Eoin: Dr. Mallett proved mathematically that by using a beam of laser light 鈥撀�

Eoin: Like we said, a real hypothetical time machine. (As in the hypothesis is real! And the math plays out.) But he hasn鈥檛 actually been able to build it. It鈥檚 too expensive. It could cost billions of dollars in the end.聽

Rebecca: And instead of finding this infuriating, Dr. Mallett is 鈥� pleased.聽

[Music]

Eoin: So what is a time from a physics standpoint? Time is malleable. Before Einstein, time and space were absolute. But Einstein showed us that the real absolute in our universe is not time or space, it鈥檚 the speed of light.聽

Einstein鈥檚 theories give us all kinds of new physics and new technologies like GPS, nuclear power, and even those old cathode-ray televisions.

Rebecca: They haven鈥檛 yet gotten us back to the past. But Einstein鈥檚 theories still open up a whole universe of ideas for all sorts of thinkers. In fact, physics is the starting point for this episode鈥檚 third and final story.聽

[Music]

Rebecca: I really wanted to talk to a science fiction writer about time. In science fiction, you can kind of hand wave the mechanics of time travel. It doesn鈥檛 need to be possible. You don鈥檛 need to fully know how time travel would work to explore all of its juicy dramatic consequences.

Eoin: Still, science fiction writers often know and incorporate a lot of physics into their stories. Even if a lot of that is left off the page.聽

Rebecca: But in a sci-fi story, the answer to the question: what is time? Is ultimately whatever the author wants it to be.

Rebecca: That鈥檚 Ted Chiang He wrote the short story that the 2016 film 鈥淎rrival鈥� is based on. It鈥檚 called 鈥�.鈥�

Both the film and the story are about a linguist who is trying to make sense of an alien language. Through that work, she begins to understand time as the aliens do. She can remember her future as well as her past.聽

Ted has written two collections of short stories. The second collection includes the time travel story, 鈥�.鈥澛� In a lot of his work, characters try to come to terms with their pasts.

Rebecca: And most of the time, these stories 鈥�

Rebecca: 鈥淭he Merchant and the Alchemist鈥檚 Gate鈥� is about a fabric merchant in medieval Baghdad. He meets a shop owner who has a time travel portal. The shop owner tells him about three others who have used the portal before the merchant decides whether or not to use it himself.聽

In the story, Ted鈥檚 rules of time travel are based on physicist Kip Thorne鈥檚 wormhole version of time travel which obeys Einstein鈥檚 theory of relativity. According to Kip Thorne, even if we could time travel, we can鈥檛 change the past.

But the vast majority of time travel fiction is about people going back and changing their past. Ted is OK with stories like that 鈥撀�

Rebecca: Ted found himself wanting to write fiction that took that less popular route.聽

Rebecca: In his story, the fabric merchant had experienced a loss 20 years before that left him hollow. He felt like he couldn鈥檛 atone for his past mistakes.聽

I鈥檓 not going to spoil the story, so all I鈥檒l say is it ends with this powerful line: 鈥淣othing erases the past. There is repentance, there is atonement, and there is forgiveness. That is all, but that is enough.鈥澛�

[Music]

[Music]

Rebecca: Sci-fi writer Ted Chiang, philosopher Heather Dyke, and physicist Ron Mallett, all explored different aspects of time. We need to look at different perspectives, because time touches every part of existence. Shifting our perspective on time can also help us make the best of the time we have.

Eoin: So Rebecca, what鈥檚 your definition of time?

Rebecca: I think time doesn鈥檛 have a neat definition. It really depends on the context. And I think back to all our interviews, and I realize why both of us always prefaced the question, 鈥淗ow do you define time?鈥澛燽y saying that it was a really unfair question. It鈥檚 so hard to define.

Eoin: It鈥檚 almost like the more we use a word the harder it is to define. And we use the word 鈥渢ime鈥� all the time.聽

Rebecca: Do you have a definition?

Eoin: Before we started this series, I came up with what I thought was a pretty good definition of time. Time, I thought, is the 鈥減erceived dimension of reality along which change occurs.鈥�

Rebecca: What do you think now?

Eoin: Now, I think I have a better definition. Time is this:

[Long pause]

Rebecca: So time is silence?

Eoin: Not necessarily silence -- it鈥檚 the thing that you鈥檙e experiencing as you experience silence. [very long pause round 2]

[Music]

Rebecca: Thanks for listening! We hope you feel inspired to read or watch a good time travel story. Don鈥檛 forget to subscribe to 鈥淩ethinking the News鈥� wherever you get your podcasts and leave us a rating or comment.

Eoin: And share this series with your friends, family, and coworkers! You can find us at csmonitor dot com slash time!

Rebecca: This series is hosted and produced by me, Rebecca Asoulin. My co-host is Eoin O鈥機arroll. It was produced with Jessica Mendoza. Editing by Samantha Laine Perfas, Clay Collins, and Noelle Swan. Sound design by Noel Flatt and Morgan Anderson. With production support from Ibrahim Onafeko.聽

This story was produced by 海角大神, copyright 2021.

[End]